1. Field of the Invention
The present invention refers to a wireless wearable pulse oximeter-based device that is based on signals supplied by two or more sensors, contained in a single housing to reduce false alarms.
A wireless wearable device measures blood oxygen saturation and/or heart rate based on two or more sensors placed in different positions of the user's body, wherein the two or more sensors share a single housing and in which the sensors are preferably of the same type. When all the sensors detect a measured value below a set of predetermined threshold values, an alarm is immediately triggered. There are different situations of the detections of the sensors that may cause the alarm to be triggered depending on a safety algorithm. The alarm can be audible, a tactile stimulus or a wireless transmitted signal sent to a receiver as, for example, a central monitoring system or a Smartphone. The wearable device can be adapted to be housed inside a wrist watch or an intelligent wrist band or on a glove. The information obtained by the sensors may be received by the device or alternatively be sent to another one.
2. General Description of the Related Art
The Obstructive Sleep Apnea Syndrome (OSAS) is a very common pathology; nearly 18 million people suffer nowadays this sickness in the USA. Several treatment approaches are available, for example the use of CPAP (Continuous Positive Airway Pressure) masks or mouth devices. The object of the present invention is to help the patients to reduce hypoxia episodes while sleeping to avoid worsening their clinic situation.
On the other hand, the Sudden Infant Death Syndrome (SIDS) might typically occur in infants one month through one year of age. It can happen to healthy children who, suddenly and inexplicably, never wake up and die. In the USA, statistics indicate that 6-7 infants die every day due to this unfortunate event and, although there are several theories that try to explain it cause, there still exists no certainty for knowing its origin.
The pulse oximeter is a well-known device that uses technology that is available since the eighties. It is non-invasive and is suitable for taking measurements on the finger of the hand. It may be obtained in several versions, for example included in multiparametric monitors connected to a central station or otherwise in portable devices. Nowadays, several technology companies are developing technical solutions for embedding them inside wrist watches of Smartphones
The following prior art documents were located:
Document U.S. Pat. No. 6,510,331 B1 (Switching device for multi-sensor array) describes a switching device interposed between a conventional oximeter and a plurality of conventional photosensors. The photosensors are located on different limbs of the body. The switching device may be operated in the manual mode or an automatic mode. In the manual mode each different photosensor may be individually selected to provide the input signal to the oximeter. In the automatic mode, the switching device scans the incoming signals from the different photosensors and forwards the best, strongest or least distorted signal to the oximeter. The device prevents the loss of oximetry information due to interrupted blood flow in a particular part of the body or the failure of a sensor. However, the device of the present invention is not located on different limbs of the body and, therefore, allows a much comfortable usage for the user.
The specification of the cited patent describes in column 2, line 12: “A switching device interposed between an oximeter and a plurality of photosensors located on various body extremities.” In column 2, line 30 the specification describes: “It is another object of this invention to provide a switching device interposed between the array of sensors and the analyzer section for selection of a particular incoming signal from one of the sensors.” However, the device of the present invention does not interpose any switching device between the sensors and the processor and, unlike the present invention, the arrangement of the US patent is not housed in a single housing.
Also, in column 2, line 41 the specification of the cited patent reads: “The switching device of this invention need not be restricted to pulsoximetry but can be used in other general measuring systems in which plural sensors are arrayed with a single display mechanism.” This suggests that the switching device can be used for measuring other type of signals, which means it is not specifically designed for being used in pulsoximetry. However, the device of the present invention is specifically designed for measuring oxygen blood saturation (Sat O2), heart rate and/or Heart Rate Variability (HRV) and in this device the user is able to deactivate any of these measurement functions. In a preferred embodiment in which the user uses the device of the present invention to avoid falling asleep (e.g. a long distance truck driver) he may deactivate the Sat O2 function.
In column 2, line 59 the specification of the cited document reads: “The switching device 10 is shown operatively connected to an oximeter/analyzer section 11 by output cable 13, in FIG. 1.” However, the device of the present invention does not include user accessible sensor connection cables and all the signal connections are embedded in the overall housing (e.g. the glove). The text of the cited document reads further: “The oximeter/analyzer section 11 and display 12 are well known in the art and operate to alternately energize the sensors 30 (shown in FIG. 3). This may let the reader infer that the oximeter/analyzer is energized by an external power supply. However, in the present invention the electrical power is supplied by a rechargeable battery.
In column 2, line 66, the specification of the cited document reads: “The switching device 10 is illustrated in the general form of a rectangular housing 14,” This allows the reader to infer that the sensors are not housed in housing 14 of the switching device 10 and are connected to it by means of cables. However, in the present invention all the elements (circuitry and sensors) are housed in a single housing (e.g. a glove).
In column 3, line 11, the specification of the cited document reads: “As shown in FIG. 1, the input connections 20 each go to an individual sensor located on a part of the body as labeled on the face of the box 14.” Here again the text mentions sensor cabling.
The cited document further reads “The sensor signals are scanned and the first or most acceptable signal is forwarded to the analyzer section. If a signal is lost, the switching device immediately selects another sensor.” The switching device analyzes the signals and selects another sensor. However, the present invention does not select or discriminate among the various sensors since all of them operate at the same time and, if all of them measure a value below a predefined threshold, the alarm generator triggers the alarm.
The cited document further reads: “The connection 20 carries power and the return signal.” However, in the present invention there is no wired power supply connection because it is housed inside the same housing.
The cited document further reads: “As shown in FIG. 3, line 24 and line 20 are connected through a plug-in on the casing 25.” However, the device of the present invention requires no external power supply.
The cited document further reads: “It is to be understood that while a certain form of the invention is illustrated, it is not to be limited to the specific form or arrangement of parts herein described and shown. It will be apparent to those skilled in the art that various changes may be made without departing from the scope of the invention and the invention is not to be considered limited to what is shown and described in the specification and drawings.” It is apparent that the document fails to reveal a wearable or wireless device and, therefore, it is totally inadequate for home usage.
U.S. Pat. No. 8,554,297 describes a body-worn system that continuously measures pulse oximetry and blood pressure, along with motion, posture, and activity level, from an ambulatory patient. The system features an oximetry probe that comfortably clips to the base of the patient's thumb, thereby freeing up their fingers for conventional activities in a hospital, such as reading and eating. The probe secures to the thumb and measures time-dependent signals corresponding to LEDs operating near 660 and 905 nm. Analog versions of these signals pass through a low-profile cable to a wrist-worn transceiver that encloses a processing unit. Also within the wrist-worn transceiver is an accelerometer, a wireless system that sends information through a network to a remote receiver, e.g. a computer located in a central nursing station. The present invention uses no cables whatsoever and also uses several sensors.
Document US 2014/200423 A1 (Wearable pulse oximetry device) describes a pulse oximetry device that is mounted on a wrist strap and fixates an area above a distal end of the ulna with a dome shaped structure. This area is used as measuring area. The measurement is carried out by a detector positioned above the fixated area that detects light emitted by light sources having different wave lengths that are located at a periphery of the fixated area. Hence, the reflections are measured at neither a reflection mode nor a transmission mode, but are at an angle between 20 DEG and 160 DEG from the emitted light. This mode, termed trans-illumination, allows achieving an excellent signal to noise ratio that for the first time enables continuous and reliable measurement of oximetry data on the wrist. The present invention uses several equal sensors. Also, the present invention can provide electric stimuli in the event an alarm is triggered.
U.S. Pat. No. 8,620,448 A1 (Non-invasive, wireless, portable device applicable to the finger to reduce the risk of sudden infant death syndrome and reduce the risk of apnea, slower heart rate, and heart arrest in all age groups) describes a device of the same applicant. However, the present invention uses several sensors inside a single housing and its object is to add more novel features to what is already described in U.S. Pat. No. 8,620,448.
Other new techniques are showing up every day, such as the single-sensor devices developed by MASIMO® (http://masimo.com/aboutmasimo/index.htm) which seem to better pick up signals even under movement and show enhanced sensitivity.